U.S. patent number 10,564,498 [Application Number 15/213,561] was granted by the patent office on 2020-02-18 for display systems and related methods involving bus lines with low capacitance cross-over structures.
This patent grant is currently assigned to A.U. VISTA INC.. The grantee listed for this patent is a.u. Vista Inc.. Invention is credited to Lee Seok Lyul.
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United States Patent |
10,564,498 |
Lyul |
February 18, 2020 |
Display systems and related methods involving bus lines with low
capacitance cross-over structures
Abstract
Display systems and related methods involving bus lines with low
capacitance cross-over structures are provided. A representative
display system includes: a first structure comprising: a plurality
of scan lines extending in a first direction; and a plurality of
data lines extending in a second direction and crossing over the
scan lines at respective cross-over locations, each of the
plurality of data lines having a pair of side walls spaced apart
from each other at each of the cross-over locations, with each of
the side walls exhibiting a height higher than portions of the data
lines not located at the cross-over locations.
Inventors: |
Lyul; Lee Seok (Hsin-Chu,
TW) |
Applicant: |
Name |
City |
State |
Country |
Type |
a.u. Vista Inc. |
Milpitas |
CA |
US |
|
|
Assignee: |
A.U. VISTA INC. (Milpitas,
CA)
|
Family
ID: |
59659625 |
Appl.
No.: |
15/213,561 |
Filed: |
July 19, 2016 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20180024406 A1 |
Jan 25, 2018 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02F
1/136286 (20130101); G02F 1/134336 (20130101); G02F
1/1368 (20130101); H01L 27/124 (20130101); H01L
27/1288 (20130101); G02F 2001/13629 (20130101); G02F
2001/136295 (20130101) |
Current International
Class: |
G02F
1/1362 (20060101); H01L 27/12 (20060101); G02F
1/1368 (20060101); G02F 1/1343 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
M396975 |
|
Jan 2011 |
|
TW |
|
I1406077 |
|
Aug 2013 |
|
TW |
|
I430448 |
|
Mar 2014 |
|
TW |
|
Other References
CN Office Action dated Mar. 29, 2019 in Chinese application (No.
201710432362.1). cited by applicant.
|
Primary Examiner: Harrison; Monica D
Assistant Examiner: Lin; John
Attorney, Agent or Firm: McClure, Qualey & Rodack,
LLP
Claims
What is claimed is:
1. A display system comprising: a first structure comprising: a
plurality of scan lines extending in a first direction; and a
plurality of data lines extending in a second direction and
crossing over the scan lines at respective cross-over locations,
each of the plurality of data lines having a pair of side walls
spaced apart from each other at each of the cross-over locations,
with each of the side walls exhibiting a first height, measured
from a bottom surface of the data line to a first top surface of
the data line at a first position where the data line overlies a
corresponding one of the scan lines, wherein portions of the data
lines not located at the cross-over locations exhibit a second
height, measured from the bottom surface of the data line to a
second top surface of the data line, with the first height being
higher than the second height.
2. The system of claim 1, wherein the side walls extend in the
second direction.
3. The system of claim 1, wherein the data lines have apertures at
the cross-over locations, and inwardly-facing surfaces of the side
walls partially define the respective apertures.
4. The system of claim 3, further comprising a bump disposed within
each of the apertures.
5. The system of claim 4, wherein the bump is in direct contact
with inwardly-facing surfaces of corresponding ones of the side
walls.
6. The system of claim 1, wherein each of the data lines has
opposing, linearly extending side surfaces, and corresponding
outwardly-facing surfaces of the side walls extend upwardly from
the side surfaces.
7. The system of claim 1, further comprising a gate insulation
layer disposed between the scan lines and the data lines.
8. The system of claim 1, wherein: the side walls are
interconnecting side walls extending across the scan lines; and the
first structure further comprises a pair of support side walls at
each of the plurality of cross-over locations, the support side
walls of each of the pairs being spaced apart from each other at
corresponding cross-over locations and extending in the first
direction.
9. The system of claim 8, wherein the support side walls and the
interconnecting side walls exhibit substantially the same
height.
10. The system of claim 1, wherein, for each of the data lines, the
bottom surface not located at the cross-over locations and the
bottom surface at the cross-over locations are coplanar.
11. A display system comprising: a substrate; a scan line supported
by the substrate and extending in a first direction; a data line
supported by the substrate and extending in a second direction such
that the data line crosses over the scan line at a cross-over
location; and gate insulation disposed between the scan line and
the data line; wherein the data line has a first section, a second
section and an interconnect section electrically interconnecting
the first section and the second section, the interconnect section
being disposed at the cross-over location, the interconnect section
having side walls defining an aperture, the interconnect section
exhibiting a first height, measured from a bottom surface of the
data line to a first top surface of the data line at a position
where the data line overlies the scan line, the first section and
the second section each exhibiting a second height, measured from
the bottom surface of the data line to a second top surface and a
third top surface of the data line, respectively, with the first
height being higher than the second height.
12. The system of claim 11, wherein the aperture is rectangular in
shape in plan view.
13. The system of claim 11, wherein the side walls are opposing
pairs of side walls, with a first of the pairs extending in the
first direction and a second of the pairs extending in the second
direction.
14. The system of claim 13, wherein the first of the pairs of side
walls are positioned outboard of the scan line.
15. The system of claim 13, wherein the first of the pairs of side
walls are inclined inwardly toward each other.
16. The system of claim 11, further comprising organic material
disposed within the aperture.
17. The system of claim 11, wherein each of the side walls exhibits
a height, corresponding to a difference between the first height
and the second height, of approximately 3.0 .mu.m.
18. The system of claim 11, wherein an inward-facing surface of a
first of the side walls is inclined with respect to a bottom of the
aperture to exhibit an angle of between approximately 45 degrees
and approximately 90 degrees.
19. The system of claim 11, wherein the bottom surface of the data
line not located at the cross-over location and the bottom surface
of the data line at the cross-over location are coplanar.
Description
BACKGROUND
Technical Field
The disclosure generally relates to signal lines of display
panels.
Description of the Related Art
Displays, such as liquid crystal displays (LCDs), are widely used
in electronic devices, such as laptops, smart phones, digital
cameras, billboard-type displays, and high-definition televisions.
In addition, electroluminescent displays such as OLEDs are also
gaining in public attention.
LCD panels may be configured as disclosed, for example, in Wu et
al., U.S. Pat. No. 6,956,631, which is assigned to AU Optronics
Corp., the parent company of the assignee of the current
application, and hereby incorporated by reference in its entirety.
As disclosed in Wu et al. FIG. 1, the LCD panel may comprise a top
polarizer, a lower polarizer, a liquid crystal cell, and a back
light. Light from the back light passes through the lower
polarizer, through the liquid crystal cell, and then through the
top polarizer. As further disclosed in Wu et al. FIG. 1, the liquid
crystal cell may comprise a lower glass substrate and an upper
substrate containing color filters. A plurality of pixels
comprising thin film transistor (TFT) devices may be formed in an
array on the glass substrate, and a liquid crystal compound may be
filled into the space between the glass substrate and the color
filter forming a layer of liquid crystal material.
Still, the structure of TFTs in displays may be various. For
instance, The TFTs, gate and data lines, and pixel electrodes may
be formed in a multilayer structure such as that shown in FIGS. 1
and 2E of Lai et al., U.S. Pat. No. 7,170,092 and in its division
U.S. Pat. No. 7,507,612, both of which are assigned to AU Optronics
Corp., the parent company of the assignee of the current
application, and both of which are hereby incorporated by reference
in their entireties. The multilayer structure may comprise a first
conducting layer, a first insulating layer, a semiconductor layer,
a doped semiconductor layer, and a second conducting layer disposed
in sequence on the substrate. It may further comprise a second
insulating layer and a pixel electrode disposed on the second
insulating layer. The first conducting layer may comprise at least
one of a gate line or a gate electrode. The doped semiconductor
layer may comprise a source and a drain. The second conducting
layer may comprise a source electrode and a drain electrode. The
multilayer structure may be formed using a series of wet and dry
etching processes, for example as disclosed in Lai et al. FIGS.
2A-2D.
Additional techniques for forming TFTs are disclosed in Chen, U.S.
Pat. No. 7,652,285, which is assigned to AU Optronics Corp., the
parent company of the assignee of the current application, and
hereby incorporated by reference in its entirety. As disclosed in
Chen, to form the channel of the TFT, the second metal layer is
etched in order to open a portion of the second metal layer over
the gate electrode and to separate the source region and drain
region. This etching can be performed in multiple ways, including
the back-channel etching process disclosed for example in Chen
FIGS. 2A-2E and the etch stop process disclosed for example in Chen
FIGS. 5A-5D and 6. Chen discloses that TFT leakage currents may be
reduced by adding a spacer layer formed at the sidewalls of the
conductive doped amorphous silicon layer, isolating the conductive
amorphous silicon layer from the insulating layer. Chen discloses
that this spacer layer can be formed by oxidizing the exposed
surface of the conductive amorphous silicon layer after the etch of
the second metal layer is performed. Chen discloses that this
surface may be oxidized by a number of different techniques,
including oxygen plasma ashing, or the use of ozone plasma in the
presence of carbon tetrafluoride and sulfur hexafluoride gases
As explained in Sawasaki et al., U.S. Pat. No. 7,557,895, which is
assigned to AU Optronics Corp., the parent company of the assignee
of the current application, and hereby incorporated by reference in
its entirety, the thickness of the liquid crystal layer typically
must be uniformly controlled, in order to avoid unevenness in
brightness across the LCD panel. As disclosed in Sawasaki et al.,
the required uniformity may be achieved by disposing a plurality of
pillar spacers between the TFT substrate and the color filter
substrate. As further disclosed in Sawasaki et al., the pillar
spacers may be formed with different heights, such that some
spacers have a height that is greater than the gap between the
substrates and other spacers have a height that is less than the
gap between the substrates. This configuration may permit the
spacing between the substrates to vary with temperature changes but
also prevent excessive deformation when forces are applied to the
panel.
Sawasaki et al. further discloses a method for assembling the
substrates with the liquid crystal material between them. This
method comprises steps of preparing the two substrates, coating a
sealing material on the circumference of the outer periphery of one
of the pair of substrates, dropping an appropriate volume of liquid
crystal on one of the pair of substrates, and filling in the liquid
crystal between the pair of substrates by attaching the pair of
substrates in a vacuum followed by returning the attached pair of
substrates to atmospheric pressure.
In LCD panels, the semiconductor material making up the TFT channel
may be amorphous silicon. However, as disclosed in Chen, U.S. Pat.
No. 6,818,967, which is assigned to AU Optronics Corp., the parent
company of the assignee of the current application, and hereby
incorporated by reference in its entirety, poly-silicon channel
TFTs offer advantages over amorphous silicon TFTs, including lower
power and greater electron migration rates. Poly-silicon may be
formed by converting amorphous silicon to poly-silicon via a laser
crystallization or laser annealing technique. Use of the laser
permits fabrication to occur at temperatures below 600.degree. C.,
and the fabricating technique is thus called low temperature
poly-silicon (LTPS). As disclosed in Chen, the re-crystallization
process of LTPS results in the formation of mounds on the surface
of the poly-silicon layer, and these mounds impact the current
characteristics of the LTPS TFT. Chen discloses a method to reduce
the size of the LTPS surface mounds, by performing a first anneal
treatment, then performing a surface etching treatment, for example
using a solution of hydrofluoric acid, and then performing a second
anneal treatment. The resulting LTPS surface has mounds with a
height/width ratio of less than 0.2. A gate isolation layer, gate,
dielectric layer, and source and drain metal layers can then be
deposited above the LTPS layer to form a complete LTPS TFT.
As disclosed in Sun et al., U.S. Pat. No. 8,115,209, which is
assigned to AU Optronics Corp., the parent company of the assignee
of the current application, and hereby incorporated by reference in
its entirety, a disadvantage of LTPS TFTs compared to amorphous
silicon TFTs is a relatively large leakage current during TFT turn
off. Use of multiple gates reduces leakage current, and Sun et al.
discloses a number of different multi-gate structures for a
polycrystalline silicon TFT, including those shown in Sun et al.
FIGS. 2A-2B and 3-6.
An alternative to LCD devices is the active matrix organic
light-emitting device (OLED), as disclosed for example in Huang,
U.S. Pat. No. 6,831,410, which is assigned to AU Optronics Corp.,
the parent company of the assignee of the current application, and
hereby incorporated by reference in its entirety. As disclosed in
Huang, a TFT is formed over a substrate. An insulating layer is
formed, covering the TFT. A contact opening is formed in the
insulating layer, exposing the drain terminal of the TFT, and an
anode layer is formed over the insulating layer and the exposed
opening, forming a contact between the anode layer and the TFT
drain terminal. A light-emitting layer is formed over the anode
layer, and a cathode layer is formed over the light-emitting layer.
As explained in Huang, there is a risk that the cathode layer will
form a short circuit with the anode layer via the contact opening.
To prevent such short circuits, Huang discloses depositing a
planarization layer that fills the space above the contact. The
light-emitting and cathode layers are then formed over the
planarization layer.
As display size is increased, various problems may become evident.
For instance, as line resistance and line capacitance increase due
to the increased line lengths, capacitive and loading effects on
scan and data lines of a display may implicate scan line delay. In
particular, rise time of a scan line driving signal may be slowed
or delayed to such an extent (e.g., greater than 0.1 T.sub.scan)
that luminance non-uniformity, flicker, cross-talk and/or image
retention problems are exhibited.
SUMMARY
Display systems and related methods involving bus lines with low
capacitance cross-over structures are provided. In one embodiment,
a display system comprises: a first structure comprising: a
plurality of scan lines extending in a first direction; and a
plurality of data lines extending in a second direction and
crossing over the scan lines at respective cross-over locations,
each of the data lines having a pair of side walls spaced apart
from each other at each of the cross-over locations, with each of
the side walls exhibiting a height higher than portions of the data
lines not located at the cross-over locations.
Another embodiment of a display system comprises: a substrate; a
scan line supported by the substrate and extending in a first
direction; a data line supported by the substrate and extending in
a second direction such that the data line crosses over the scan
line at a cross-over location; and gate insulation disposed between
the scan line and the data line; wherein the data line has a first
section, a second section and an interconnect section electrically
interconnecting the first section and the second section, the
interconnect section being disposed at the cross-over location, the
interconnect section having side walls defining an aperture, the
side walls extending higher than heights exhibited by the first
section and the second section.
In another embodiment, a method for manufacturing a display system
comprises: providing a substrate; supporting a first metal layer
with the substrate to form a plurality of scan lines extending in a
first direction; providing a bump over each of the scan lines; and
providing a second metal layer with a portion of the layer
extending partially over an exterior of each of the bumps to form a
plurality of data lines extending in a second direction and
crossing over the scan lines at respective cross-over locations
such that the second metal layer forms side walls spaced apart from
each other by a corresponding one of the bumps for each of the data
lines.
Other objects, features, and/or advantages will become apparent
from the following detailed description of the preferred but
non-limiting embodiments. The following description is made with
reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of an embodiment of an LCD
system.
FIG. 2 is a schematic diagram of the embodiment of FIG. 1 showing
detail of a bus cross-over location.
FIGS. 3A-3B through 9A-9B are schematic, cross-sections (as viewed
along section lines similar to section line 3-3 of FIG. 2) showing
representative process steps for manufacturing an embodiment.
FIG. 10 is a flowchart depicting an embodiment of a method for
manufacturing a display system.
DETAILED DESCRIPTION
For ease in explanation, the following discussion describes
embodiments of the present disclosure in the context of a display
system, such as a liquid crystal display (LCD) system or organic
light emitting diode (OLED) display system. It is to be understood
that the invention is not limited in its application to the details
of the particular arrangements shown since the invention is capable
of other embodiments. Also, the terminology used herein is for the
purpose of description and not of limitation.
In this regard, display systems and related methods involving bus
lines with low capacitance cross-over structures are provided. In
some embodiments, the bus lines may incorporate side walls that
interconnect segments of bus lines at cross-over locations. So
configured, capacitance of the lines at the cross-over locations
may be reduced without significantly increasing resistance.
Exemplary embodiments will now be described with reference to the
drawings.
With reference to FIG. 1, an embodiment of a display system 100
configured as an LCD panel is depicted. Fundamentally, display
system 100 includes an LCD panel 110 with a plurality of pixels,
data control circuitry 120 and gate control circuitry 130. The
circuits and functions can be implements by hardware, software or a
combination of hardware and software such as microcontrollers,
application-specific integrated circuits (ASIC) and programmable
microcontrollers.
LCD panel 110 incorporates a plurality of pixels (typically
thousands of pixels, e.g., pixels 140, 150), which are arranged in
a two-dimensional array comprising a plurality of rows and columns.
For ease of illustration, only a few pixels are shown. As is known,
in a thin film transistor (TFT) LCD panel, a pixel is typically
formed from three pixel elements (PEs): one red, one green, and one
blue, although various configurations may be used. For instance,
pixel 150 is depicted as including three PEs-PE(R), PE(G) and
PE(B). One or more transistors and one or more storage capacitors
are typically coupled to each pixel element, thereby forming
driving circuitry for the associated pixel element.
The transistors of all pixels in a given row typically are
connected to bus lines--their gate electrodes are connected to a
gate (scan) line (e.g., line 154), and their source electrodes are
connected to a source (data) line (e.g., line 152). The gate
control circuitry 130 and data control circuitry 120 control the
voltage applied to the respective gate and data bus lines to
individually address each pixel element in the LCD panel. By
controllably pulsing the respective pixel element driving
transistors, the driving circuits can control the transmissivity of
each PE, and thereby control the color of each pixel. The storage
capacitors assist in maintaining the charge across each pixel
between successive pulses (which are delivered in successive
frames). Common lines (not shown) provide reference (common)
signals for the electrodes.
A portion of the embodiment of FIG. 1 is depicted schematically in
FIG. 2, in which detail of a bus cross-over location 160 is
presented. In particular, as shown in FIG. 2, gate line 154 extends
in a first direction and is provided as a strip of material that
exhibits generally uniform rectangular cross-sections along its
length. Gate line 154 includes top and bottom (generally planar)
surfaces 162 and 164, respectively, and opposing side surfaces 166
and 168 that are substantially parallel to each other. Gate line
154 exhibits a width W.sub.g.
As shown in FIG. 2, data line 152 extends in a second direction
that is generally perpendicular to the first direction of gate line
154, although other configurations may be used in other
embodiments. Data line 152 includes top and bottom (generally
planar) surfaces 172 and 174, respectively, and opposing side
surfaces 176 and 178 that are substantially parallel to each other.
Data line 152 exhibits a width W.sub.d.
Data line 152 incorporates first and second segments (182 and 184,
respectively) each of which exhibits generally uniform rectangular
cross-sections along its length. A cross-over segment 186
interconnects segments 182, 184, with cross-over segment 186 being
positioned at cross-over location 160 (i.e., the location at which
data line 152 crosses over gate line 154). It should be noted that
although not depicted for ease of illustration, one or more of
various other materials and/or features may be provided at a
cross-over location, such as a gate insulating material disposed
between lines 152 and 154, for example.
Cross-over segment 186 includes an aperture 188 that defines a void
190 (which may be at least partially filled in some embodiments)
that is positioned over gate line 154. In this embodiment, aperture
188 is generally rectangular in plan view and incorporates inner
surfaces of side walls 191, 192, 193 and 194. Specifically, side
walls 191 and 193 are aligned with the second direction and form
the interconnecting structure of cross-over segment 186 as side
walls 191 and 193 span the width of gate line 154 to electrically
connect segments 182 and 184. Side walls 192 and 194 are aligned
with the first direction and are positioned outboard of gate line
154.
Each of the side walls 191-194 protrudes upwardly from surface 172
and exhibits a height (H.sub.s) (not including the thickness of
data line 154) of between approximately 1 .mu.m and approximately 5
.mu.m (e.g., approximately 3.0 .mu.m), and a width (W.sub.s) of
between approximately 0.1 .mu.m and approximately 0.7 .mu.m (e.g.,
approximately 0.3 .mu.m). By providing the sidewalls, line
resistance of the cross-over segment may be controlled (e.g.,
reduced) while improving the mechanical stability of line 152 in
the vicinity of vid 190.
In contrast to conventional bus cross-overs that exhibit a
capacitance (C) of .epsilon.(S/d), where .epsilon. is the
dielectric constant between the lines, S is the overlapping surface
area of the lines and d is the distance separating the lines, thus
.epsilon.((w.sub.dw.sub.g)/d), the embodiment of FIG. 2 exhibits a
capacitance of .epsilon.((2w.sub.sw.sub.g)/d), where
2w.sub.s<w.sub.d. In some embodiments, the reduction in surface
area of the cross-over segment when compared to a conventional line
of uniform area (a relationship of 2w.sub.s to w.sub.d) can result
in a reduction in capacitance of between approximately 20% and
approximately 60% (e.g., approximately 40%). Of significance, this
may be accomplished without significantly increasing (and in some
cases maintaining) line resistance owing to the increase in
conductive line material used (e.g., the material used in forming
the extended height of the side walls 191 and 193).
FIGS. 3A-3B through 9A-9B are schematic, cross-sections showing
representative process steps for manufacturing an embodiment of a
display system. Each cross-section shown in FIGS. 3B-9B is
respectively observed from the cross-section lines 3B-3B through
9B-9B marked in FIGS. 3A-9A. As shown in FIGS. 3A and 3B, a
representative first step in the process involves providing a
substrate 202 and forming a first metal layer 204 on an upper
surface of the substrate. Metal layer 204, which may comprise Al,
Cu, Mo or metal alloy, for example, may be deposited by sputtering
or thermal evaporation. Metal layer 204 is used to form a gate
line.
In FIGS. 4A-4B, a gate insulation layer 206 is deposited on a top
surface of metal layer 204. Additionally, a semiconductor device
207 (for example, an active layer configured as a channel of a
switching device such as a thin film transistor (TFT)) also is
formed. The material of the semiconductor device 207 may be, for
example, amorphous Silicon, low temperature poly-Silicon or Indium
Gallium Zinc oxide.
In FIGS. 5A-5B, a bump 208 is formed over the gate insulation layer
206. The bump 208 is made of an organic layer. The organic layer is
formed over the gate insulation layer 206. The organic layer, which
may be acrylate, epoxy or siloxane, for example, is formed by spin
coating or slit coating. The organic layer is configured in the
form of a bump 208 with a height of approximately 2-3 .mu.m. Also
depicted in FIG. 3C is a layer of photoresist 210 deposited on top
of bump 208. Notably, the photoresist applied to the bump exhibits
an overhang portion.
As shown in FIGS. 6A-6B, a second metal layer 212 is deposited. By
way of example, the metal may be Al, Cu or metal alloy, for
example. Notably, metal layer 212 adheres to the side walls (e.g.,
side walls 214, 216) of bump 208, and forms a cap 218 about the
exposed upper surfaces of photoresist 210.
In FIGS. 7A-7B, photoresist 220 is applied to facilitate formation
of a data line, a source electrode 221 and a drain electrode 223 of
a TFT, which are formed after metal etching is performed as
depicted in FIGS. 8A-8B, which removes material down to the gate
insulation layer in areas not covered by the photoresist. The
photoresist is subsequently removed by stripper as shown in FIGS.
9A-9B.
As shown in FIGS. 9A-9B, in addition to the photoresist 210 and 220
being removed, the cap 218 is removed along with the photoresist
(this removal technique is known as the lift-off method). Thus, the
remaining structure incorporates substrate 202, metal layer 204
(configured as a gate line), gate insulation layer 206, bump 208
and metal layer 212 (configured as a data line).
The data line formed from metal layer 212 incorporates a cross-over
segment 230 that includes side walls (e.g., side walls 232 and
234). Cross-over segment 230 electrically interconnects segments
236 and 238 of the data line using side walls similar to side walls
232 and 234 (although the interconnecting side walls are not
illustrated in FIG. 3F due to the cross-sectional perspective. The
side walls extend outwardly from the generally planar top surface
of the data line and may be inclined inwardly toward each other,
such that each exhibits an angle (.theta.) of between approximately
45 and approximately 90 degrees, preferably between approximately
70 and approximately 90 degrees. The angle of inclination of the
side walls is determined, at least in part, by the angle of the
exterior surface of the bump that is in contact with the metal
layer 212.
A flowchart depicting an embodiment of a method for manufacturing a
display system is depicted in FIG. 10. As shown in FIG. 10, the
process may be construed as beginning at block 250, in which a
substrate is provided. In block 252, a first metal layer is
provided on the substrate for forming a gate line. Then, in block
254, a gate insulation layer is provided on the first metal layer.
The metal layer and the gate insulation layer can be provided
through a process such as Physical Vapor Deposition, Chemical Vapor
Deposition or printing.
In block 256, a bump (e.g., a bump of organic material) is provided
on the gate insulation layer. The bump can be provided through a
process such as Physical Vapor Deposition, Chemical Vapor
Deposition or printing. Then, as shown in block 258, a second metal
layer is provided. The second metal layer can be provided through a
process such as Physical Vapor Deposition, Chemical Vapor
Deposition or printing. In particular, the second metal layer is
configured as a data line that includes side walls extending
partially over the exterior of the bump (e.g., up the sides of the
bump) to form a cross-over segment. In some embodiments, formation
of the side walls may be accomplished by one or more of various
process steps, such as by performing a lift-off method to remove a
cap formed over the top of the bump. This may involve selectively
applying photoresist, upon which a portion of the second metal
layer is deposited. In particular, the photoresist is located over
the bump. Additional photoresist is then applied for forming
various features, such as may be provided by performing a metal
etch. Thereafter, all the photoresist is removed, which also lifts
off the portion of the second metal layer that was formed on top of
photoresist, thereby forming an aperture in the second metal layer
and exposing the bump (see, FIGS. 6A-6B to 9A-9B, for example). The
lift-off method may be performed through dissolving the photoresist
by solvent.
By reducing capacitive and loading effects on scan and data lines
of a display with a cross-over segment, scan line delay may be
correspondingly reduced. As such, the desire for increased display
size may be accommodated without the conventional drawbacks of
luminance non-uniformity, flicker, cross-talk and/or image
retention problems.
The embodiments described above are illustrative of the invention
and it will be appreciated that various permutations of these
embodiments may be implemented consistent with the scope and spirit
of the invention.
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